Conical inlet transition zone for mechanical refiners

ABSTRACT

Conical inlet refiner elements for a mechanical refiner include: a conical stator element disposed between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and a conical rotor element disposed between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element. The conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap at a feedstock inlet to a primary refining gap formed between the primary refining plates, where the primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.

BACKGROUND

Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to being prior art by inclusion in this section.

Mechanical refiners for treating fibrous material typically include two refiner elements substantially opposite to one another. One of the refiner elements, the rotor, is arranged to move with respect to a stationary refiner element, the stator. Between the rotor and the stator, a refiner gap is created into which the fibrous material to be refined is fed. The refiner elements include the refining surfaces that carry out the actual refining. The refining surfaces may be one integral structure, or they may consist of a plurality of refining surface segments arranged adjacent to one another forming the refining surface.

FIG. 1A is a diagram illustrating a mechanical refiner 100 having a ribbon feeder type mechanism 150 for conveying feedstock 145 into the mechanical refiner 100. The mechanical refiner 100 may include a rotor plate 110, and a stator plate 120. Rotation of the rotor plate 110 around an axis of rotation 105 may be caused by a motor (not shown) via a rotor shaft 135. A refining gap 140 may be formed between refining surfaces of the rotor plate 110, and the stator plate 120.

In some cases, the fibrous material, also referred to as feedstock 145, is introduced into the mechanical refiner 100 by the ribbon feeder type mechanism 150. The feedstock 145 is fed into the area of the rotor plate 110 and the stator plate 120 in a substantially axial (e.g., horizontal direction). The axial feedstock inlet flow must then be redirected into a radial direction (e.g., a substantially perpendicular plane) to enter the refining gap 140 between the rotor plate 110 and the stator plate 120.

FIG. 1B is a diagram illustrating another mechanical refiner 160 having a blowline type feedstock feeding mechanism. In FIG. 1B, feedstock 145 is pumped under pressure by a feedstock pump (not shown) into the area of the rotor plate 110 and stator plate 120 in a substantially axial (e.g., horizontal direction), and the inlet feedstock flow must also be redirected into a radial direction (e.g., a substantially perpendicular plane) to enter the refining gap 140 between the rotor plate 110 and the stator plate 120.

As the inlet feedstock flow enters the mechanical refiner, the feedstock 145 encounters a flinger plate 115 at a center portion of the rotating rotor plate 110. The rotating flinger plate 115 may use a small number of vanes (e.g., 4-6 vanes) to cause the horizontally flowing feedstock 145 to be redirected by centrifugal force through several individual openings into a plane substantially perpendicular to the horizontal feedstock inlet flow. The small number of vanes of the flinger plate 115 and the individual openings may can cause uneven distribution of the feedstock to the primary refining gap, resulting in uneven loads on the motor of the mechanical refiner.

SUMMARY

Apparatuses and methods for providing a conical inlet transition zone for a mechanical refiner are provided.

According to various aspects there is provided conical inlet refiner elements for a mechanical refiner. In some aspects, the conical inlet refiner elements may include: a conical stator element disposed between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; a conical rotor element disposed between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element. The conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap at a feedstock inlet to a primary refining gap formed between the primary refining plates. The primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.

According to various aspects there is provided a mechanical refiner. In some aspects, the mechanical refiner may include: conical inlet refiner elements including a conical stator element disposed between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and a conical rotor element disposed between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element. The conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap at a feedstock inlet to a primary refining gap formed between the primary refining plates. The primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.

According to various aspects there is provided a method for providing a conical inlet transition zone for a mechanical refiner. In some aspects, method may include: installing a conical stator element on a stator of the mechanical refiner between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and installing a conical rotor element on a rotor of the mechanical refiner between the feedstock inlet to the mechanical refiner and the primary refining plates. The conical rotor element is configured to form an initial refining gap with the conical stator element. The conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap of the pre-refining zone at a feedstock inlet to a primary refining gap formed between the primary refining plates. The primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects and features of the various embodiments will be more apparent by describing examples with reference to the accompanying drawings, in which:

FIG. 1A is a diagram illustrating a mechanical refiner having a ribbon feeder type feedstock feeding mechanism;

FIG. 1B is a diagram illustrating another mechanical refiner 160 having a blowline type feedstock feeding mechanism;

FIG. 2 is a side view of an example of a conical inlet refining elements for a conical pre-refining zone according to some aspects of the present disclosure

FIG. 3 is a diagram illustrating an example of a mechanical refiner including conical inlet refining elements according to some aspects of the present disclosure;

FIG. 4 is a diagram illustrating an example of a portion of a mechanical refiner having a conical pre-refining zone according to some aspects of the present disclosure;

FIG. 5 is a diagram illustrating an example of a configuration of conical inlet refining elements in a pre-refining zone according to some aspects of the present disclosure;

FIG. 6A is a diagram illustrating an example of a conical rotor element for a conical pre-refining zone according to some aspects of the present disclosure;

FIG. 6B is a perspective view of an example of a conical rotor element for a conical pre-refining zone according to some aspects of the present disclosure;

FIG. 7 is a perspective view of an example of a conical stator element for a conical pre-refining zone according to some aspects of the present disclosure; and

FIG. 8 is a flowchart illustrating a method for providing a conical inlet transition zone for a mechanical refiner according to some aspects of the present disclosure.

DETAILED DESCRIPTION

While certain embodiments are described, these embodiments are presented by way of example only, and are not intended to limit the scope of protection. The apparatuses, methods, and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes in the form of the example methods and systems described herein may be made without departing from the scope of protection.

Similar reference characters indicate corresponding parts throughout the several views unless otherwise stated. Although the drawings represent embodiments of various features and components according to the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate embodiments of the present disclosure, and such exemplifications are not to be construed as limiting the scope of the present disclosure.

Mechanical refiners for refining fibrous material may include two primary refiner elements: a rotating rotor plate and a stationary stator plate. Each of the rotor plate and the stator plate include refining surfaces between which a gap is formed into which the fibrous material, also referred to as feedstock, is fed to carry out the actual refining. The refining gap formed between the refining surfaces of the primary refiner elements (e.g., the rotor plate and the stator plate) may be referred to as a primary refining gap. The refining surface of each primary refiner element may be one integral structure or may consist of a plurality of refining surface segments arranged adjacent to one another forming the refining surface.

According to aspects of the present disclosure, a conical inlet refining zone, also referred to herein as a pre-refining zone or an initial refining zone, may be provided for a mechanical refiner. The initial refining zone can provide pre-refining of the feedstock before it enters the primary refining gap. Pre-refining by conical elements forming the initial refining zone can more evenly distribute the feedstock to the primary refining gap and even out the load on the motor of the mechanical refiner. The conical elements forming the initial refining zone can also provide a continuous (e.g., 360 degree) opening for better distribution of the feedstock by conveying the feedstock to the primary refining gap on a conical path.

FIG. 2 is a side view of an example of a conical inlet refining elements 200 for a conical pre-refining zone 210 according to some aspects of the present disclosure. A conical pre-refining zone 210 may be formed by a conical rotor element 220 and a conical stator element 230, also referred to herein as conical inlet refining elements. The conical inlet refining elements 200 may be disposed in the mechanical refiner between a feedstock inlet to the mechanical refiner and the primary refining plates of the mechanical refiner. The conical pre-refining zone 210 formed by the conical inlet refining elements 200 may provide pre-refining of the feedstock prior to entry of the feedstock to the primary refining zone formed by the primary refining plates.

Referring to FIG. 2 , the conical inlet refining elements 200 may include a rotatable conical rotor element 220 and a stationary conical stator element 230. The rotatable conical rotor element 220 may be coupled to the rotor (not shown) of the mechanical refiner. The stationary conical stator element 230 may be coupled to the stator (not shown) of the mechanical refiner.

The conical rotor element 220 may include a conical rotor ring 222 and a set of rotor segments 225. The conical rotor ring 222 may be configured to mount the set of rotor segments 225 at a predetermined radial angle with respect to an axial feedstock flow path 145 into the mechanical refiner. Each rotor segment 225 may include a series of bars and grooves forming a refining area configured to provide the pre-refining action for the feedstock.

The conical stator element 230 may include a conical stator ring 232 and a set of stator segments 235. The conical stator ring 232 may be configured to mount the set of stator segments 235 at a predetermined radial angle with respect to an axial feedstock flow path 145 into the mechanical refiner. The predetermined radial angle of the conical stator ring 232 may be substantially the same as the predetermined radial angle of the conical rotor ring 222 or may be different than the predetermined radial angle of the conical rotor ring 222. Each stator segment 235 may include a series of bars and grooves forming a refining area configured to provide the pre-refining action for the feedstock.

A refining gap between the conical stator element 230 and the conical rotor element 220 in the conical pre-refining zone 210 may be determined based on the requirements of the main refining zone. For example, when a finer refined feedstock is required to be produced by the main refining zone, a narrower refining gap may be set for the conical pre-refining zone 210. Conversely, if only a coarser refined feedstock is required to be produced by the main refining zone, a wider refining gap may be set for the conical pre-refining zone 210.

The refining gap for the conical pre-refining zone 210 may be set by adjusting the position of the conical stator element 230 with respect to the primary stator refining plates. For example, shims may be used to adjust the position of the conical stator element 230. Other methods of adjusting the position of the conical stator element 230 may be used without departing from the scope of the present disclosure. Alternatively, the position of the conical rotor element 220 with respect to the conical stator element 230 may be adjusted. For example, shims may be used to adjust the position of the conical rotor element 220. Other methods of adjusting the position of the conical rotor element 220 may be used without departing from the scope of the present disclosure.

FIG. 3 is a diagram illustrating an example of a mechanical refiner 300 including conical inlet refining elements according to some aspects of the present disclosure. Referring to FIG. 3 , the mechanical refiner 300 may include a rotor plate 310 having a rotor plate refining surface 315 and a stator plate 320 having a stator plate refining surface 325. A primary refining gap 340 may be formed between the rotor plate refining surface 315 and the stator plate refining surface 325.

A conical rotor ring 350 may be coupled to the rotor 360, for example by fasteners or another method. A set of rotor segments 355 may be coupled to the conical rotor ring 350, for example by fasteners. The set of rotor segments 355 may be mounted on the conical rotor ring 350 at a predetermined angle forming a conical rotor element. The predetermined angle may be provided by the configuration of the conical rotor ring 350. The predetermined angle may be a radial angle greater than zero but less than 90 degrees with respect to a direction of axial feedstock flow path 145. In some implementations, the predetermined angle may be a radial angle in a range of 10 degrees to 20 degrees with respect to the direction of axial feedstock flow path 145.

In some implementations, a single conical rotor refining surface rather than a set of individual rotor segments may be mounted on the conical rotor ring to perform the pre-refining operation on the feedstock. In some implementations, a single conical rotor refining surface rather than a set of individual rotor segments may be mounted on the conical rotor ring to perform the pre-refining operation on the feedstock. In some implementations, the conical rotor ring and conical rotor refining surface may be formed as a single conical piece.

A conical stator ring 370 may be coupled to the stator 380, for example by fasteners or another method. A set of stator segments 375 may be coupled to the conical stator ring 370, for example by fasteners. The set of stator segments 375 may be mounted on the conical stator ring 370 at a predetermined angle forming a conical stator element. The predetermined angle may be provided by the configuration of the conical stator ring 370. The predetermined angle may be a radial angle greater than zero but less than 90 degrees with respect to a direction of an axial feedstock flow path 145. In some implementations, the predetermined angle may be a radial angle in a range of 10 degrees to 20 degrees with respect to the direction of axial feedstock flow path 145.

In some implementations, a single conical stator refining surface rather than a set of individual stator segments may be mounted on the conical stator ring to perform the pre-refining operation on the feedstock. In some implementations, the conical stator ring and conical stator refining surface may be formed as a single conical piece.

The set of rotor segments 355 and the set of stator segments 375 may form a conical refining surface of an initial refining zone 390. The initial refining zone 390 can provide pre-refining of the feedstock before it enters the primary refining gap 340. Pre-refining by the conically mounted set of rotor segments 355 and the conically mounted set of stator segments 375 forming the initial refining zone can more evenly distribute the feedstock 145 to the primary refining gap and result in more even loading of the motor of the mechanical refiner. A continuous (e.g., 360 degree) opening may be formed by the conical elements to provide better distribution of the feedstock 145 by conveying the feedstock from the conical refining surface of the pre-refining zone to the primary refining gap on a conical path.

FIG. 4 is a diagram illustrating an example of a portion of a mechanical refiner 400 having a conical pre-refining zone according to some aspects of the present disclosure. Referring to FIG. 4 , a feeding mechanism 405, for example, a ribbon-type feeding mechanism or other feeding mechanism, may convey feedstock 145 in an axial flow path (e.g., substantially horizontal flow path) into the mechanical refiner 400. The feedstock 145 may be conveyed into a pre-refining gap, also referred to herein as an initial refining gap 410 between the rotor segments 425 and the stator segments 435. The rotor segments 425 and the stator segments 435 may include a series of bars and grooves forming a refining area configured to provide pre-refining of the feedstock 145 before distributing the feedstock 145 via a continuous (e.g., 360 degree) opening of the conical pre-refining zone into the primary refining zone 460 between the primary rotor plate 470 and the primary stator plate 480.

As illustrated in FIG. 4 , the angle provided by the rotor segments 425 mounted on the conical rotor ring 420 and the stator segments 435 mounted on the conical stator ring 430 may redirect the feedstock flow path 145 in a radial direction as it is refined in the initial refining gap 410. As the feedstock 145 exits the initial refining gap 410, the pre-refined feedstock 145 is distributed in a continuous (e.g., 360 degree) feed from the conical pre-refining zone into the primary refining zone 460 between the primary rotor plate 470 and the primary stator plate 480. The primary refining zone 460 lies in a plane substantially perpendicular to the axial (e.g., horizontal) feedstock flow path 145 as it enters the mechanical refiner 400. The radial angle provided by the conical pre-refining zone can redirect the axial feedstock flow path 145 in a radial direction to improve the feedstock flow into the primary refining zone 460.

FIG. 5 is a diagram illustrating an example of a configuration of conical inlet refining elements in a pre-refining zone according to some aspects of the present disclosure. Referring to FIG. 5 , a set of rotor segments 525 may be mounted on a conical rotor ring 520. The conical rotor ring 520 may be configured to provide a predetermined mounting angle θ for the set of rotor segments 525. The predetermined angle θ may be a radial angle greater than zero but less than 90 degrees with respect to a direction of axial feedstock flow path 145 in the axial direction of the rotor shaft 305 of the mechanical refiner. In some implementations, the predetermined angle θ may be a radial angle in a range of 10 degrees to 20 degrees with respect to the direction of axial feedstock flow path 145. In some implementations, the predetermined angle θ may be a radial angle of approximately 15 degrees. Similarly, the conical stator ring 530 may be configured to mount a set of stator segments 535 at the predetermined radial angle θ.

The rotor segments mounted on the conical rotor ring 520 and the stator segments 535 mounted on the conical stator ring 530 may form an initial refining gap 540 having the predetermined radial angle θ. The horizontal feedstock flow path 145 entering the initial refining gap 540 may be redirected by an amount equal to the predetermined radial angle θ in a radial direction towards the primary refining zone 550. The pre-refined feedstock exiting the initial refining gap 540 may be distributed in a continuous (e.g., substantially 360 degree) feed from the conical pre-refining zone into the primary refining zone 550.

FIG. 6A is a diagram illustrating an example of a conical rotor element 600 for a conical pre-refining zone according to some aspects of the present disclosure. As illustrated in FIG. 6A, the conical rotor ring 610 may be coupled to the rotor shaft 630 of the mechanical refiner. The conical rotor ring 610 is configured to provide the predetermined radial angle θ for mounting the set of rotor segments 615. Feedstock 145 flowing in an axial (e.g., horizontal) direction may be redirected by an amount equal to the predetermined radial angle θ in a radial direction towards the primary refining gap.

FIG. 6B is a perspective view of an example of a conical rotor 600 element for a conical pre-refining zone according to some aspects of the present disclosure. As illustrated in FIG. 6B, a series of bars and grooves 620 is formed on each rotor segment of the set of rotor segments 615. The series of bars and grooves of each rotor segment and each stator segment may be formed at an angle selected to ensure that the pre-refined feedstock exiting the conical pre-refining zone will be substantially uniformly distributed into the primary refining zone. Selection of the angle for the bars and grooves may take into account a coefficient of friction between the feedstock and the bars and grooves as well as the predetermined mounting angle θ for the rotor segments. In some implementations, the series of bars and grooves of each rotor segment may be formed at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path 145. Other angles for the bars and grooves that enable pre-refining and distribution of the pre-refined feedstock may be used without departing from the scope of the present disclosure.

FIG. 7 is a perspective view of an example of a conical stator element 700 for a conical pre-refining zone according to some aspects of the present disclosure. As illustrated in FIG. 7 , a series of bars and grooves 720 is formed on each stator segment of the set of stator segments 715. The series of bars and grooves of each stator segment and each stator segment may be formed at an angle selected to ensure that the pre-refined feedstock exiting the conical pre-refining zone will be substantially uniformly distributed into the primary refining zone. Selection of the angle for the bars and grooves may take into account a coefficient of friction between the feedstock and the bars and grooves as well as the predetermined mounting angle θ for the stator segments. In some implementations, the series of bars and grooves of each stator segment may be formed at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path 145. Other angles for the bars and grooves that enable pre-refining and distribution of the pre-refined feedstock may be used without departing from the scope of the present disclosure.

FIG. 8 is a flowchart illustrating a method for providing a conical inlet transition zone for a mechanical refiner according to some aspects of the present disclosure. The conical inlet transition zone may be provided as part of an initial buildup of a new mechanical refiner or as a retrofit for an existing mechanical refiner. Referring to FIG. 8 , at block 810, a flinger plate may optionally be removed from the rotor. For an initial buildup of a mechanical refiner, a flinger plate may not yet be installed and accordingly will not need to be removed. For a retrofit application with an existing flinger plate, the flinger plate may be removed.

At block 820, a conical rotor ring may be installed on the rotor. The conical rotor ring may be coupled to the rotor shaft of the mechanical refiner, for example, by mechanical fasteners such as bolts or by another method. The conical rotor ring is configured to provide the predetermined radial angle θ for mounting the set of rotor segments.

The predetermined angle θ may be a radial angle greater than zero but less than 90 degrees with respect to a direction of axial feedstock flow path in the axial direction of the rotor shaft of the mechanical refiner. In some implementations, the predetermined angle θ may be a radial angle in a range of 10 degrees to 20 degrees with respect to the direction of axial feedstock flow path. In some implementations, the predetermined angle θ may be a radial angle of approximately 15 degrees. Feedstock flowing in an axial (e.g., horizontal) direction may be redirected by an amount equal to the predetermined radial angle θ in a radial direction towards the primary refining gap.

At block 830, a set of rotor segments may be installed on the conical rotor ring. The set of rotor segments may be coupled to the conical rotor ring, for example by mechanical fasteners or by another method. The set of rotor segments may be mounted on the conical rotor ring at the predetermined angle thereby forming a conical rotor element. The predetermined angle may be provided by the configuration of the conical rotor ring. In some implementations, a single conical rotor refining surface rather than a set of individual rotor segments may be may be mounted on the conical rotor ring to perform the pre-refining operation on the feedstock. In some implementations, the conical rotor ring and conical rotor refining surface may be formed as a single conical piece.

A series of bars and grooves is formed on each rotor segment of the set of rotor segments or on the single conical rotor refining surface. The series of bars and grooves may be formed at an angle selected to ensure that the pre-refined feedstock exiting the conical pre-refining zone will be substantially uniformly distributed into the primary refining zone. In some implementations, the series of bars and grooves of each rotor segment or on the single conical rotor refining surface may be formed at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path. Other angles for the bars and grooves that enable pre-refining and distribution of the pre-refined feedstock may be used without departing from the scope of the present disclosure.

At block 840, a conical stator ring may be installed on the stator. The conical stator ring may be coupled to the stator of the mechanical refiner, for example, by mechanical fasteners such as bolts or by another method. The conical stator ring is configured to provide the predetermined radial angle θ for mounting the set of stator segments.

The predetermined angle θ may be a radial angle greater than zero but less than 90 degrees with respect to a direction of axial feedstock flow path in the axial direction of the rotor shaft of the mechanical refiner. In some implementations, the predetermined angle θ may be a radial angle in a range of 10 degrees to 20 degrees with respect to the direction of axial feedstock flow path. In some implementations, the predetermined angle θ may be a radial angle of approximately 15 degrees. Feedstock flowing in an axial (e.g., horizontal) direction may be redirected by an amount equal to the predetermined radial angle θ in a radial direction towards the primary refining gap.

At block 850, a set of stator segments may be installed on the conical stator ring. The set of stator segments may be coupled to the conical stator ring, for example by mechanical fasteners or by another method. The set of stator segments may be mounted on the conical stator ring at the predetermined angle thereby forming a conical stator element. The predetermined angle may be provided by the configuration of the conical stator ring. In some implementations, a single conical stator refining surface rather than a set of individual stator segments may be mounted on the conical stator ring to perform the pre-refining operation on the feedstock. In some implementations, the conical stator ring and conical stator refining surface may be formed as a single piece.

A series of bars and grooves is formed on each stator segment of the set of stator segments or on the single conical stator refining surface. The series of bars and grooves may be formed at an angle selected to ensure that the pre-refined feedstock exiting the conical pre-refining zone will be substantially uniformly distributed into the primary refining zone. In some implementations, the series of bars and grooves of each stator segment or on the single conical stator refining surface may be formed at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path. Other angles for the bars and grooves that enable pre-refining and distribution of the pre-refined feedstock may be used without departing from the scope of the present disclosure.

The specific operations illustrated in FIG. 8 provide a particular method for providing a conical inlet transition zone for a mechanical refiner according to an embodiment of the present disclosure. Other sequences of operations may also be performed according to alternative embodiments. For example, alternative embodiments of the present disclosure may perform the operations outlined above in a different order. Moreover, the individual operations illustrated in FIG. 8 may include multiple sub-operations that may be performed in various sequences as appropriate to the individual operation. Furthermore, additional operations may be added or removed depending on the particular applications.

According to aspects of the present disclosure, a conical inlet refining zone (e.g., a pre-refining zone or an initial refining zone) for a mechanical refiner is provided. The conical inlet refining zone can provide pre-refining of the feedstock before it enters the primary refining gap. Pre-refining the feedstock by the initial refining zone can more evenly distribute the feedstock in a continuous (e.g., 360 degree) conical path to the primary refining gap and even out the load on the motor of the mechanical refiner. The conical refining elements for the conical inlet refining zone may be installed during new buildup of a mechanical refiner or maybe retrofit to existing mechanical refiners. In addition, providing the conical inlet refining zone may enable the use of wider primary refining gap thereby extending the life of the primary refining plates.

The examples and embodiments described herein are for illustrative purposes only. Various modifications or changes in light thereof will be apparent to persons skilled in the art. These are to be included within the spirit and purview of this application, and the scope of the appended claims, which follow. 

What is claimed is:
 1. Conical inlet refiner elements for a mechanical refiner, the conical inlet refiner elements comprising: a conical stator element disposed between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and a conical rotor element disposed between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element, wherein the conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap at a feedstock inlet to a primary refining gap formed between the primary refining plates, and wherein the primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.
 2. The conical inlet refiner elements of claim 1, wherein the conical stator element and the conical rotor element are configured to cause the radial change in the direction of the axial feedstock flow path in a range of 10 degrees to 20 degrees.
 3. The conical inlet refiner elements of claim 1, wherein the conical stator element and the conical rotor element are configured to cause an approximately 15 degree radial change in the direction of the axial feedstock flow path.
 4. The conical inlet refiner elements of claim 1, wherein the conical rotor element comprises a set of rotor segments, each rotor segment comprising a series of bars and grooves defining a refining area.
 5. The conical inlet refiner elements of claim 4, wherein the series of bars and grooves of each rotor segment are formed at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path.
 6. The conical inlet refiner elements of claim 4, wherein the conical rotor element further comprises a conical rotor ring configured to mount the set of rotor segments to a rotor of the mechanical refiner at a predetermined angle in a radial direction with respect to an axial direction of the mechanical refiner.
 7. The conical inlet refiner elements of claim 6, wherein the predetermined angle is approximately 15 degrees.
 8. The conical inlet refiner elements of claim 1, wherein the conical stator element comprises a set of stator segments, each stator segment comprising a series of bars and grooves defining a refining area.
 9. The conical inlet refiner elements of claim 8, wherein the series of bars and grooves of each stator segment are formed at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path.
 10. The conical inlet refiner elements of claim 8, wherein the conical stator element further comprises a conical stator ring configured to mount the set of stator segments to a stator of the mechanical refiner at a predetermined angle in a radial direction with respect to an axial direction of the mechanical refiner.
 11. The conical inlet refiner elements of claim 10, wherein the predetermined angle is approximately 15 degrees.
 12. A mechanical refiner, comprising: conical inlet refiner elements including: a conical stator element disposed between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and a conical rotor element disposed between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element, wherein the conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap at a feedstock inlet to a primary refining gap formed between the primary refining plates, wherein the primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.
 13. The mechanical refiner of claim 12, wherein the conical stator element and the conical rotor element are configured to cause the radial change in the direction of the axial feedstock flow path in a range of 10 degrees to 20 degrees.
 14. The mechanical refiner of claim 12, wherein the conical stator element and the conical rotor element are configured to cause an approximately 15 degree radial change in the direction of the axial feedstock flow path.
 15. The mechanical refiner of claim 12, wherein the conical rotor element comprises a set of rotor segments, each rotor segment comprising a series of bars and grooves defining a refining area, wherein the series of bars and grooves of each rotor segment are set at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path.
 16. The mechanical refiner of claim 15, wherein the conical rotor element further comprises a conical rotor ring configured to mount the set of rotor segments to a rotor of the mechanical refiner at a predetermined angle in a radial direction with respect to an axial direction of the mechanical refiner.
 17. The mechanical refiner of claim 12, wherein the conical stator element comprises a set of stator segments, each stator segment comprising a series of bars and grooves defining a refining area, wherein the series of bars and grooves of each stator segment are set at an angle in a range of 45 degrees to 60 degrees with respect to the axial feedstock flow path.
 18. The mechanical refiner of claim 17, wherein the conical stator element further comprises a conical stator ring configured to mount the set of stator segments to a stator of the mechanical refiner at an angle of approximately 15 degrees in a radial direction with respect to an axial direction of the mechanical refiner.
 19. A method for providing a conical inlet transition zone for a mechanical refiner, the method comprising: installing a conical stator element on a stator of the mechanical refiner between a feedstock inlet to the mechanical refiner and primary refining plates of the mechanical refiner; and installing a conical rotor element on a rotor of the mechanical refiner between the feedstock inlet to the mechanical refiner and the primary refining plates, the conical rotor element configured to form an initial refining gap with the conical stator element, wherein the conical stator element and the conical rotor element are configured to cause a radial change greater than zero but less than 90 degrees in a direction of an axial feedstock flow path through the initial refining gap of the conical inlet transition zone at a feedstock inlet to a primary refining gap formed between the primary refining plates, wherein the primary refining gap formed between the primary refining plates lies in a plane that is approximately perpendicular to the axial feedstock flow path.
 20. The method of claim 19, wherein the conical rotor element comprises a set of rotor segments mounted to the rotor at a predetermined angle in a radial direction with respect to an axial direction of the mechanical refiner, and wherein the conical stator element comprises a set of stator segments mounted to the stator at a predetermined angle in a radial direction with respect to an axial direction of the mechanical refiner, wherein the predetermined angle is an angle in a range of 10 degrees to 20 degrees in a radial direction with respect to an axial direction of the mechanical refiner. 